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Graphtec GL840-M

  • Graphtec GL840 data logger - side.
  • Graphtec GL840 data logger.
  • Graphtec GL840 data logger features.
  • Graphtec GL840 data logger channel expansion distance.
  • Graphtec GL840 data logger channel expansion.
  • Graphtec APS software.
  • Graphtec APS software monitoring.
  • Graphtec APS software schedule.
$2,805.00 (inc GST) $2,550.00 (exc GST)
3.00 KGS
Call for availability.
Calculated at checkout

Product Description

The Graphtec GL840 is a multi-channel data logger that can be used for many data logging applications. There are two versions of this data logger manufactured by Graphtec. The GL840-M which is used for general data logging work, and the GL840-WV which has improved temperature accuracy and it can also handle higher DC voltages.

What can the GL840-M measure and record?

While the GL840-M can be used on many different types of data logging and monitoring projects. We commonly see our customers using the GL840-M data logger to record some of the following parameters for a fairly wide and varied list of applications.

  • Calibration Laboratories - Temperature recording for general calibration and verification work.
  • Commercial Office Air Quality Studies - Temperature, Humidity Light(Lux), Noise, and Comfort.
  • Autoclave - General calibration and verification of temperature and pressure plus spacial profiling.
  • Motor vehicle and Trucks - Temperature and pressures for engine oil, exhaust systems, gearbox, differentials and axles.
  • Battery condition monitoring and measurement. Also see the GL840-WV for higher voltage.
  • Furnace and Ovens - Temperature monitoring and profiling.
  • Yacht and bout hull building - Temperature measurement of e-glass and composite.
  • Diesel engine temperatures and pressures plus engine RPM speed.
  • Consumer appliance testing - Temperature testing of thermal safety fuses and general R&D testing.
  • Rail - Rolling stock, braking systems air pressure, bearing temperatures.
  • Air conditioning and HVAC systems - Temperature, humidity and power consumption for energy efficiencies.
  • Pharmaceutical - Temperature monitoring and data logging for manufacturing and product storage.

Looking at the list above, temperature is the stand out parameter. We mostly see customers using thermocouples to measure temperature because they are generally well priced, easy to use and their accuracy can be typically better than ±1°C if required. If better accuracy is needed, the GL840-M also supports three wire RTD(PT100) sensors too. On occasions with see  customers using temperatures transmitters with 4-20mA outputs. The GL840-M can also measure 4-20mA signals with the use of an standard external 250 ohm resistor, plus the GL840-M then has a dedicated input range for easy data scaling back to Deg C.

After the temperature, pressure, humidity and energy would be the next most common. Although the list flattens out sharply.

When would you use a GL840-M?

The GL840-M is a great data logger for any project, small or large.  It does start to stand out for those projects where you need to record ten or more sensors, but no more than two hundred sensors. This could be a mix of various sensor types, or they could all be the same type of sensors.

Why would you use a GL840-M?

In one word, Simplicity. The Graphtec GL840-M is quick and easy to set up and use. You can literally take the GL840-M out of the box, connect a couple of thermocouples to the terminals, use the on-board keypad to set the required channels and sampling rate, then press the Start button. Recorded data can be quickly save to an SD memory card in CSV format and then be viewed directly in Microsoft Excel or any other software program that can import CSV data. It's that simple and you haven't even installed the free Graphtec GL software!


Graphtec GL840 features


Graphtec GL840-M

  • Type: General purpose data logger.
  • Channels: 20 - expandable to 200.
  • Inputs: Voltage, Current*, Temperature, Humidity and Logic I/O.
  • Speed: 10ms to 1hr.
  • Resolution: 16bit.
  • Data Storage: Internal 4GB flash memory.
  • PC Connection: Ethernet & USB 2.0.
  • Data transfer: SD memory card, direct to PC or via optional WiFi module.
  • Power: Power: Optional Graphtec Battery B-569 or External 8.5~24 volts DC.
  • Software: Software included and freely available via download.

GL840 Technical Specifications. Download

GL840 Quick Start Guide (26 MB) Download

GL840 Users Manual (21 MB) Download

GL840 Application Software Download

Options Summary

  • Graphtec genuine B-569 battery.
  • Graphtec B-568 WiFi module.
  • Graphtec B-513 Logic Input/Output cable.
  • Graphtec B-530 Humidity probe.
  • GL840 carry case.
  • See expansion modules below.

Channel Input types

Voltage Input voltage range 20 mV to 100V
Maximum voltage (Input to GND) 60 Vp-p
Temp. Thermocouple types R, S, B, K, E, T, J, N, W (WRe5-26)
RTD (Resistance Temp. Detector) Pt100 (IEC751), JPt100 (JIS), Pt1000 (IEC751)
Pulse Flow Total or Instantaneous pulse counting.
RPM RPM pulse counting.
Accuracy Voltage ± 0.1% of F.S.


± 1.55 ºC

*Accuracy rating for K-type thermocouple at 100°C includes reference junction compensation. Accuracy varies by the temperature levels and thermocouple types. See this post about calibrating your Graphtec data logger.

Up to 200 isolated channels with multifunction input

The GL840 is fitted with 20 channels as standard. It can be expanded from 20 to 200 channels with the optional B-567 cables, B-566 expansion base plus either the B-564 or B-565 expansion module. A total of 500 channels can be monitored via the Graphtec APS software and up to 10 GL840-M units can be networked as a complete data logging solution.

 20 Channels
40 Channels
100 Channels
200 Channels
Graphtec GL840-M or GL840-WV Data Logger unit 1 1 1 1
Extension Cable B-567-05 or B-567-20 -- 1 1 1
Channel Expansion base plate B-566 -- 2 5 10
20Ch Expansion terminal B-564(GL840-M) or B-565(GL840-WV) -- 1 4 9

If you required a 40 channel system. Please order the following items.

1 x GL840-M or GL840-WV data logging units.
1 x Extension cable B-567-05 or B-567-20.
2 x B-566 channel expansion base plate.
1 x 20Ch expansion terminal B-564(GL840-M) or B-565(GL840-WV).

The B-564 terminal that is supplied fitted to the GL840-M is first removed from the data logger, it is then fitted to the first B-566 base, the additional B-564 terminal is fitted to the second B-566 base, both terminal base sets are now connected together using the supplied fixing plates and screws, the B-567-05 cable connects to terminal base sets to the GL840-M.

Graphtec GL840 channel expansion.

Maximum sampling interval of up to 10ms

Voltage measurements can be sampled as fast as 10mS for one channel. Thermocouple measurements can be sampled at a maximum rate of 100mS for ten channels.

Sampling Interval10ms20ms50ms100ms200ms500ms1s2s
Number of channels 1 2 5 10 20 50 100 200
Measuring type Voltage Yes Yes Yes Yes Yes Yes Yes Yes
Thermocouple N/A N/A N/A Yes Yes Yes Yes Yes

Supports SD memory card for reliable long term data storage or transfer

The Graphtec GL840 data logger supports one SD memory card slot for data storage or transfer. The SDHC type SD memory card is supported up to 32GB.

Binary or ASCII data file types

The captured data can be stored in GBD(Graphtec binary data) or CSV file format. The binary data format is more robust and a lot more compacted than the CSV format. The CSV format has the direct advantage in that it can be opened directly in MS Excel or other data analysis software programs.

GBD format 41 days 88 days 103 days 207 days Over 365 Over 365 Over 365
CSV format 3 days 11 days 16 days 36 days 91 days 182 days Over 365

*Figures are approximate. Maximum file size of captured data is 2GB in GBD or CSV file format.

Vivid 17.8cm(7") TFT colour LCD...

The bright, easy-to-read 17.8cm(7") TFT colour LCD monitor (VGA: 800 x 480 dots) makes it even easier to review measurement parameter settings, measured waveforms, and digital values.

All the GL840's functions can be accessed through the navigation cluster and LCD screen. Single touch buttons for such tasks as display mode, set up and logging start/stop negate the need for complicated menu trees.

Free Bundled PC software

The GL840-M is bundled with PC application software that enables data logging directly to a PC. In addition to waveform monitoring, this software provides other useful functions such as direct writing of data to an Excel file and report creation. The software also provides a Help display function for enhanced usability.

Diverse measurement screens

Various display screens can be selected: Y-T, X-Y, Digital, Meter, and Report.

Multi-channel measurement

One GL840-M data logger enables measurement on up to 200 channels at the device itself, and up to 500 channels when PC measurement has been specified. In addition, since the channels can be assigned to four display groups, they can be arranged according to the input type.

Convenient functions

A function that displays the logic alarm status during measurement and a password protection function are built in. Other convenient functions are the display of a CSV file batch conversion screen after captured data has been replayed and various data search functions.

Software Features

  • Configuration and channel set up via USB or Ethernet Real time data storage to hard disk.
  • Stored data import from GL840-M.
  • Email notification of errors and alarms.
  • Available measurement modes: Y-T and X-Y.
  • Separate screens are available for each of the settings.
  • Direct Excel transfer can be enabled as a report function.

Remote monitoring via Ethernet; Web server/FTP functions

Your PC’s Firefox, Opera or Internet Explorer applications can be used for settings, control, data monitoring and data acquisition.

The Web server function enables the acquisition of setting control data.

The FTP function enables the acquisition of data stored to the GL840-M.

GL840-M Main Features

  • 20 input channels as standard, expandable to 200 channels.
  • Isolated multifunction channels for Voltage, Temperature or Humidity.
  • Inputs: Voltage (20mv to 50V), Thermocouples (K,E,J,T,N,R,S,T,B,W) and 4-20mA signals via external shunt resistor.
  • Optional Graphtec B-530 Humidity sensor is available.
  • Four pulse inputs and one trigger input. Optional Graphtec B-513 cable required.
  • 16-bit ADC resolution.
  • 17.8cm (7") colour LCD display (VGA: 800 x 480 dots).
  • Waveform and text display modes.
  • Easy-to-use keypad menu system.
  • Single open-collector alarm output.
  • Range of trigger functions.
  • Real-time statistical calculation.
  • USB 2.0 interface for PC connection.
  • Ethernet (TCP/IP) for PC connection and WEB/FTP server.
  • Optional Graphtec battery B-569 for portable operation.
  • Scan speed - Maximum.
    • 10 milli Seconds for 1 channel.
    • 20 milli Seconds for 2 channels.
    • 50 milli Seconds for 5 channels.
    • 100 milli Seconds for 1-10 channels.
    • 200 milli Seconds for 11-20 channels.
    • 500 milli Seconds for 21-50 channels.
    • 1 Second for 51-100 channels.
    • 2 Seconds for 101-200 channels

The GL840-M includes the following:

  • GL840 Quick Start Guide.
  • GL840-APS Software on CD.
  • Mains Power Supply - 24Volts DC.
  • USB Cable for PC connection.

Warranty Information

2 years warranty.

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